One control unit can be for control of one or more electric devices. Control communication with the electric devices can be by multiple data channels. A serial interface can provide for connection between the electric devices and the control unit through a serial link. Using the multiple data channels, parallel data can be sent out to the electric devices through a serial data stream to provide a synchronous downstream data transmission. Further, the control unit can receive feedback data sent from the electric devices in an asynchronous upstream data transmission.
With the data received from the control unit, the respective electric device can obtain information to generate a device clock signal. The respective electric device can use the generated device clock signal in the asynchronous upstream data transmission.
As requirements in terms of the amount of control data to be transmitted to electric devices and in terms of frequency of such control data transmissions to be performed become more stringent, time slots available for an individual control signal in a channel to be physically transmitted get shorter to a point where the conventional control is too unreliable to be safely used.